Glutamate is a major neurotransmitter but possesses also a wide metabolic function in the body. It is released from approximately 40% of synaptic terminals and mediates many physiological functions by activation of different receptor types (Watkins and Evans (1981) Excitatory amino acid transmitters, Annu. Rev. Pharmacol., 21: 165-189; Gasic and Hollmann (1992) Molecular neurobiology of glutamate receptors, Annu. Rev. Physiol., 54: 507-536). Two main categories of glutamate receptors have been identified, ionotropic and metabotropic (Bettler and Mulle, (1995) Neurotransmitter Receptors II, AMPA and Kainate Receptors, Neuropharmacology, 34: 123-139; Pin and Duvoisin (1995) Neurotransmitter receptors I, The Metabotropic Glutamate Receptors: Structure and Functions, Neuropharmacology, 34: 1-26; Mori and Mishina (1995) Neurotransmitter Receptors VIII, Structure and Function of the NMDA Receptor Channel, Neuropharmacology, 34: 1219-1237). Ionotropic glutamate receptors can be subdivided into N-methyl-D-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA), and kainate receptors. Metabotropic glutamate receptors can be subdivided into three classes, mGluRI, mGluRII and mGluRIII (Pin and Duvoisin (1995) Neurotransmitter receptors I, The Metabotropic Glutamate Receptors: Structure and Functions, Neuropharmacology, 34: 1-26). Five receptor subunits form the functional NMDA receptor which is modulated by glycine and polyamines and blocked by Mg2+. Activation of NMDA receptors leads to influx of Na+- and K+-ions into the cell as well as Ca2+-ions, either through the receptor channel itself or through voltage dependent Ca2+-channels (Bettler and Mulle, (1995) Neurotransmitter Receptors II, AMPA and Kainate Receptors, Neuropharmacology, 34: 123-139; Mori and Mishina (1995) Neurotransmitter Receptors VIII, Structure and Function of the NMDA Receptor Channel, Neuropharmacology, 34: 1219-1237). Four different subunits, named GluR1-GluR4, form the AMPA receptor channel. AMPA receptors are highly permeable to Na+- and K+-ions. AMPA receptor assemblies lacking the GluR2 subunit are also permeable to Ca2+-ions (Hollmann M, Heinemann S (1994): Cloned glutamate receptors, Annu. Rev. Neurosci., 17: 31-108).
Kainate receptors are built from five subunits, GluR5-7 as well as KA1 and KA2. Kainate receptor associated ion channels are permeable to Na+- and K+-ions as well as Ca2+. Ca2+-permeability of kainate receptor associated ion channels is dependent on the presence of the GluR6 subunit within the receptor complex (Hollmann M, Heinemann S (1994): Cloned glutamate receptors, Annu. Rev. Neurosci., 17: 31-108). There is considerable experimental and clinical evidence indicating that glutamate is involved in the pathogenesis of neuronal degeneration in the context of hypoxia/ischemia and trauma of the central nervous system, seizures and hypoglycemia. In addition, glutamate is thought to be involved in the pathogenesis of chronic neurodegenerative disorders, such as amyotrophic lateral sclerosis, Huntington's, Alzheimer's and Parkinson's disease. Functional glutamate receptors have been also identified in lung, muscle, pancreas and bone (Mason D J, Suva L J, Genever P G, Patton A J, Steuckle S, Hillam R A, Skerry T M (1997) Mechanically regulated expression of a neural glutamate transporter in bone: a role for excitatory amino acids as osteotropic agents? Bone 20: 199-205; Patton A J, Genever P G, Birch M A, Suva L J, Skerry T M (1998) Expression of an N-methyl-D-aspartate-type receptor by human and rat osteoblasts and osteoclasts suggests a novel glutamate signaling pathway in bone, Bone 22; 645-649). However, no link has been established so far between glutamate receptor stimulation and tumor growth.
Many forms of cancer have been described affecting every form of tissue known in man. Of the described forms of human cancer, none is curable in 100% of the affected patients. Treatment modes include surgical removal, chemotherapy with cytostatic agents alone or in combination with hormone receptor modulators and/or steroids and/or interferons, and radiation (Hill R (1992): Cellular basis for radiotherapy, in The Basic Science of Oncology, McGraw-Hill, pp. 259-275).
I. The term inhibitor of the interaction of glutamate with the AMPA receptor complex applies to:
1. all agents that bind to the AMPA receptor and prevent or reduce the binding of glutamate to the AMPA binding site in a competitive- or non-competitive manner. These are antagonists of the binding of glutamate to the AMPA receptor;
2. all agents that do not bind to the AMPA receptor binding site but bind or interact with AMPA receptor modulatory sites and thus prevent glutamate from triggering the signal that would occur when glutamate binds to the AMPA binding site;
3. all agents that interact directly with the AMPA-ion channel, i.e. AMPA receptor channel blockers. These agents reduce permeability of the ion channels associated with the AMPA receptor to ions (preferably Na+, K+ and/or Ca2+);
4. all agents that decrease the release of glutamate from nerve endings or other tissues and thus prevent glutamate from binding to the AMPA binding sites and from triggering the signal that would occur as a result of binding of glutamate to AMPA binding site;5. all agents that decrease synthesis of glutamate and thus prevent glutamate from binding to its binding sites;6. all agents that increase the metabolism of glutamate and therefore prevent glutamate from triggering the signal that would occur as a result of binding of glutamate to its binding sites;7. all agents that increase the uptake of glutamate and thus decrease the binding of glutamate to AMPA binding site;8. all agents that interfere with glutamate transporter systems and decrease the concentration of glutamate in synaptic cleft and thus prevent glutamate from triggering the signal that would occur as a result of binding of glutamate to its binding sites;9. all agents that interact with glutamate and prevent its binding to the AMPA receptor. Such compounds include i.e. glutamate partial agonists or molecules binding to glutamate;10. antibodies to AMPA receptor subunits, or to the AMPA receptor, or to glutamate decreasing the binding of glutamate to AMPA binding site.II. The term inhibitor of the interaction of glutamate with the KA receptor complex applies to:1. all agents that bind to the KA receptor and prevent or reduce the binding of glutamate to the KA binding site in a competitive- or non-competitive manner. These are antagonists of the binding of glutamate to the KA receptor;2. all agents that do not bind to the KA receptor binding site but bind or interact with KA receptor modulatory sites and thus prevent glutamate from triggering the signal that would occur when glutamate binds to the KA binding site;3. all agents that interact directly with the KA-Ion channel, i.e. KA receptor channel blockers. These agents reduce permeability of the ion channels associated with the KA receptor to ions (preferably Na+, K+ and/or Ca2+).4. all agents that decrease the release of glutamate from nerve endings or other tissues and thus prevent glutamate from binding to the KA binding sites and from triggering the signal that would occur as a result of binding of glutamate to KA binding site;5. all agents that decrease synthesis of glutamate and thus prevent glutamate from binding to its binding sites;6. all agents that increase the metabolism of glutamate and therefore prevent glutamate from triggering the signal that would occur as a result of binding of glutamate to its binding sites;7. all agents that increase the uptake of glutamate and thus decrease the binding of glutamate to KA binding site;8. all agents that interfere with glutamate transporter systems and decrease the concentration of glutamate in synaptic cleft and thus prevent glutamate from triggering the signal that would occur as a result of binding of glutamate to its binding sites;9. all agents that interact with glutamate and prevent its binding to the KA receptor. Such compounds include e.g. glutamate partial agonists or molecules binding to glutamate;10. antibodies to KA receptor subunits, or to the KA receptor, or to glutamate decreasing the binding of glutamate to KA binding site.III. The term inhibitor of the interaction of glutamate with the NMDA/glycine/polyamine receptor complex applies to:1. all agents that bind to the NMDA receptor or NMDA ion channel associated glycine or polyamine binding site and prevent or reduce the binding of glutamate to the NMDA binding site in a competitive- or non-competitive manner. These are antagonists of the interaction of glutamate with the NMDA receptor;2. all agents that do not bind to the NMDA receptor binding site but bind or interact with NMDA receptor modulatory sites and thus prevent glutamate from triggering the signal that would occur when glutamate binds to the NMDA binding site;3. all agents that interact directly with the NMDA-ion channel, i.e. NMDA receptor channel blockers. These agents reduce permeability of the ion channels associated with the NMDA receptor to ions (preferably Na+, K+ and Ca2+).4. all agents that decrease the release of glutamate from nerve endings or other tissues and thus prevent glutamate from binding to the NMDA binding sites and from triggering the signal that would occur as a result of binding of glutamate to NMDA binding site;5. all agents that decrease synthesis of glutamate and thus prevent glutamate from binding to NMDA and NMDA channel associated binding sites;6. all agents that increase the metabolism of glutamate and therefore prevent glutamate from triggering the signal that would occur as a result of binding of glutamate to NMDA and NMDA channel sites;7. all agents that increase the uptake of glutamate and thus decrease the binding of glutamate to NMDA binding site;8. all agents that interfere with glutamate transporter systems and decrease the concentration of glutamate in synaptic cleft and thus prevent glutamate from triggering the signal that would occur as a result of binding of glutamate to NMDA binding sites;9. all agents that interact with glutamate and prevent its binding to the NMDA receptor. Such compounds include e.g. glutamate partial agonists or molecules binding to glutamate;10. antibodies to NMDA receptor subunits, or to the NMDA receptor, or to glutamate decreasing the binding of glutamate to NMDA binding site.
Various glutamate antagonists and receptor channel blockers that are within the scope of the present invention will now be described in greater detail:
A. AMPA Receptor Antagonists
AMPA receptor antagonists refer to compounds that bind to AMPA receptors in a competitive manner or interact with AMPA receptor associated sites and block AMPA mediated signal in a non-competitive manner.
Such antagonists include L-glutamate derivatives, amino alkanoic acid derivatives, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate derivatives, acetyl-aminophenyl-dihydro-methyl-dioxolo-benzodiazepine, acid amide derivatives, amino-phenyl-acetic acid, 2,3-benzodiazepin-4-one, alkoxy-phenyl-benzodiazepine, amino- or desamino-2,3-benzodiazepine, benzothiadiazine, β-carboline-3-carboxylic acid, fused cycloalkylquinoxalinediones, decahydroisoquinoline, 4-hydroxypyrrolone, 4-hydroxy-pyrrolo-pyridazinone, imidazo-pyrazinone, imidazolo-quinoxalinone, indeno-pyrazine-carboxylic acid, indeno-pyrazinone, indoloneoxime, indolo-pyrazinone, isatine, isatinoxime, oxadiazole, phenyl-azolophthalazine, phenylpyridazino-indole-1,4-dione, quinoline, quinolinone, quinoxaline, quinoxalinedione, quinazolinone, quinolone, nitroquinolone, and sulphamate derivatives.
B. AMPA Receptor Channel Blockers
AMPA receptor channel blockers refer to compounds that reduce the permeability of channels associated with the AMPA receptor to cations (preferably to Na+, K+ and/or Ca2+ ions). AMPA receptor channel blockers can therefore be used to prevent a signal being transmitted due to ionic flux that would otherwise occur when glutamate binds to the AMPA receptor.
AMPA receptor channel blockers include e.g. fluorowillardiine, Joro spider toxin, NSTX spider toxin, argiotoxin.
C. KA Receptor Antagonists
KA receptor antagonists refer to compounds that bind to KA receptors in a competitive manner or interact with KA receptor associated sites and block KA mediated signal in a non-competitive manner.
Such antagonists include L-glutamate derivatives, kainic acid derivatives, acid amide derivatives, aminoalkanoic acid derivatives, aminophenyl(alkyl)acetic acid derivatives, fused cycloalkylquinoxalinediones, quinoxalinedione, imidazolo-quinoxalinone, isatine, phenyl-azolophthalazine, pyridothiazines, 4-phosphonoalkyl-quinolinone, quinolinone, quinazoline, quinazolinedione, quinoxalinedione and sulphamate derivatives.
D. KA Receptor Channel Blockers
KA receptor channel blockers refer to compounds that reduce the permeability of channels associated with the KA receptor to cations (preferably to Na+, K+ and/or Ca2+ ions). KA receptor channel blockers can therefore be used to prevent a signal being transmitted due to ionic flux that would otherwise occur when glutamate binds to the KA receptor.
KA receptor channel blockers include i.e. Joro spider toxin, NSTX spider toxin and argiotoxin 636.
E. NMDA/Glycine/Polyamine Receptor Antagonists
NMDA/glycine receptor antagonists refer to compounds that bind to NMDA receptors in a competitive manner or interact with NMDA receptor associated sites and block NMDA mediated signal in a non-competitive manner.
Such antagonists include L-glutamate derivatives, tetrahydroquinolines, imidazoloquinoxalinones, isatines, fused cycloalkylquinoxalinediones, quinoxalines, spermine, 4-hydroxy-3-nitro-1,2-dihydroquinolon-2-one derivatives, indole derivatives, benzo-thiadiazine dioxide derivatives, indeno(1,2-b)pyrazin-3-ones or corresponding 2,3-diones, quinoline derivatives, ethyl(phenyl-carbamoyl)-ethenyl)dichloroindole carboxylates, thienopyrazine 2,3-dione derivatives, 2-(2,3-dicarboxycyclopropyl) glycine, 2-amino-3-substituted phenyl propionic acid derivatives, 1-carboxyalkylquinoxaline-2.3(1H,4H)dione derivatives, thienyl-glycine derivatives, benzo-fused azacyclic compounds, tricyclic quinoxaline-diene derivatives, 3-hydroxy anthranilic acid and salts, decahydroisoquinolines, tri- or terta-substituted guanidine derivatives, D- or L-tryptophan derivatives, tetrazolyl(alkyl)-cyclohexyl-aminoacid derivatives, octahydrophenanthrene derivatives, benzomorphan, piperazinyl or piperidinyl-alkyl substituted isoxazole derivatives, decahydroisoquinoline-3-carboxylic ester or its amide preparation, compounds based on Conantokin-G peptide, 3-heterocyclyl-alkyl-benzopyran-2-one derivatives, phosphono-alkyl imidazo-pyrimidine carboxylic acid derivatives, amantadine, memantine, rimantidine, histogranin and analogues, nitrobenzoic acid derivatives, e.g 4-((2-methoxycarbonyl-4-nitrophenyl)methyl)piperazine carboxylic acid, diamine derivatives with selective sigma receptor affinity, remacemide (2-amino-N-(1,2-diphenyl-1-methylethyl)acetamide), phosphono-alkylidene- or phosphono-alkoxy-imino-piperidine acid, benzothiadiazine carboxylic acid derivatives, dihydro-benzothiadiazine dioxide carboxylic acid derivatives, 4-hydroxy 2(H) pyrrolone derivatives, quinoxaline derivatives, tetrahydro-imidazo(1,2-a)pyrimidines or their salts, 4-hydroxy-pyrrolo(1,2-b)pyridazin-2(1H)-one derivatives, nitroquinolone derivatives, 3-aryl-substituted 2(1H)quinolone, 2(1H)-quinolone, phosphonic acid quinoline-2-carboxylic acid derivatives, benzimidazole(s) carrying 2 acidic groups, N,N′-disubstituted guanidine derivatives, tricyclic quinoxalinediones, 2-(2,3-dicarboxycyclopropyl) glycine, isatine derivatives, 3-amino-indolyl-derivatives, 2-phenyl-1,3-propanediol dicarbamate (felbamate), benzomorphan derivatives, dihydrothienopyridine derivatives, (aminophenyl)-heteroaryl ethylamine, pyridazinedione derivatives, a 2H-1-benzopyran-2-one compound, a 4-sulphonylamino-quinoline derivative, R(plus)-3-amino-1-hydroxy-pyrrolidine-2-one, 2-carboxy indole, substituted. imino-methano dibenzo(A,D)cycloheptene derivatives, indole-hydrazone, piperazine derivatives, 4,6-disubstituted tryptophan and kynurenine derivatives, fluorenamine, diketo-pyridopyrazine derivatives or its salts, 2-amino-3,4-dioxo-1-cyclobutene derivatives, 2-acyl-amido derivatives of 3,4-dihydro-3-oxo-quinoxaline, benzimidazole phosphono-aminoacid derivatives, quinoxaline phosphono-aminoacid derivatives, piperazine, piperidine or pyrrolidone derivatives, its salts and isomeric forms including stereoisomers, 4-hydroxy-2(1H)-quinolinone derivatives, its salts and prodrugs, fused pyrazine derivatives, 2-phenyl or 2-thienyl-(2)-piperidine derivatives, 3-amido or 3-sulphamido-indolyl derivatives, 3-aryl-4-hydroxy-2-(1H)-quinolone derivatives, 2-heterocyclyl-2-hydoxy-ethylamine derivatives, 1-aryl-2-aminomethyl pyrrolidine, its optical isomers and acid-addn. salts, 4,6-dihalo indole-2-carboxylic acid derivatives, cyclic amino-hydroxamate derivatives, tetracyclic amine derivatives, 2,4-dioxo-1,2,3,4-tetrahydroquinoline derivatives, 2,4-dioxo-1,2,3,4-tetrahydroquinoline derivatives, 3-phosphonopiperidine and p-pyrrolidine derivatives, benzothieno(2,3-B)-pyrazine-2,3-(1H,4H)-dione, spiro dibenzosuberane derivatives, benzomorphan derivatives, preparation of 3,4-disubstituted 2-isoxazoline(s) and isoxazoles(s), 3-indolyl thio-acetate derivatives, arginine-derived nitric oxide biosynthesis inhibitors, dicyclic amine derivatives, spiroisoindole derivatives, imidazo(1,2-A)-pyridinylalkyl, 1,2,3,4-tetrahydro-9H-pyridoindole or benzothiophene derivatives, indole-2,3-dione-3-oxime derivatives, 1-aryl-2-(aminomethyl)cyclopropanecarboxamide derivatives, 4-phosphono-2-amino-alkenoic acid derivatives, naphthopyran derivatives, beta-ketone, beta oxime or beta hydrazine phosphonate, topa quinone aminoacid, kynurenic acid, quinoline- or thienopyridine-carboxylic acid derivatives, 10,5-(imino-methano)-10,11-dihydro-5H-dibenzo(A,D)cycloheptene or its derivatives, bicyclic amino-hydroxamate derivatives, indole-2-carboxylic acid derivatives, substituted adamantane derivatives, benzobicycloalkane derivatives, 2,4-disubstituted-1,2,3,4-tetrahydro-quinoline derivatives, dihydro-alkyl-substituted-(immunomethano)-5H-dibenzo-cycloheptene, aryl-cyclohexylamine, N-substituted. benzobicycloalkane amine, isoquinoline phosphonates, N,N′-disubstituted.-guanidine, phosphonopropenyl piperidine carboxylic acid, (2R,3S,4S)-alpha-carboxy-cyclopropyl-glycine, pyrrolidine derivatives, dihydroxy-fused heterocyclyl quinoxaline derivatives, hydrogenated derivatives of MK 801 and analogues, 5-substituted 10,11-dihydro 5H-dibenzo(a,d)cycloheptene5,10-imine, 11-exo-hydroxy MK 801 preparations, tetra hydro-isoquinoline or 2-benzazepine derivatives, N-3-phenyl-propionyl-substituted. spermine or related polyamine derivatives, 4-amino-fluorene or its heterocyclic analogues, cyclooctane-imine derivatives, R-3-amino-1-hydroxy pyrrolidin-2-one or methionine hydroxamate, 10,11-dihydro-5H-dibenzo-cyclohepten-5,10-imine, polyhydro-10,11-dihydro-5H-benzo(a,d)cyclohepten-5,10 imine derivatives, 4-oxo-1,4-dihydroquinoline with 2-acidic groups, heterocyclyl-alkene-phosphonic acid, phosphono group-containing pyridine 2-carboxylic acid, alpha-amino-alpha-(3-alkylphenyl)alkyl ethanoic acid, its esters or amides, 10,11-dihydro-5H-dibenzo-A,D-cyclohepten-5,10-imine, phosphorus containing unsatturated amino acids or their salts, 5 substituted-1-,11-dihydro-5H-dibenzo-cyclohepten-5,10-imine or analogues, heterocyclic phosphonic acid derivatives or their salts, substituted 4-(amino-carbonyl-amino)quinoline derivatives, tricyclic quinoxaline derivatives, butyryl-tyrosine spermine or one of its analogues, tri- or tetra-substituted guanidine, quinoxalinylalkyl-aminoalkane phosphonic acid derivatives, 2-(aminophenyl)-3-(2-carboxy-indol-3-yl)-propenoic acid derivatives, 6-piperidinylpropionyl-2(3H)-benzoxazolone derivatives, 6-(3-[4-(4-fluorobenzyl)piperidin-1-yl]propionyl)-3H-benzoxazol-2-one or its salts, imidazo(1,2-a)pyridine, tetrahydroquinoline derivatives or their salts, 2-methyl-5,8-substituted 2,3,4,5-tetra- or 2,3,4,4a,5,9b-hexahydro-1H-pyrido[4,3-b]indole, 3-aminoindolyl, 6-pyrrolyl-quinoxaline-2.3-dione derivatives, imidazolyl-(mercaptoalkyl)-quinoxaline-dione, 3-amidoindolyl derivatives, heterocyclyl-imidazolo-quinoxalinone, naphthyl-substituted alpha-amino acid derivatives, 5-hetero-aryl-2,3-quinoxaline-dione derivatives, quinoxaline derivatives, 5H,10H-imidazo indeno 4-pyrazinone derivatives, hydroxy-(aryl-substituted phenyl)-quinolone, imidazo indolo pyrazinone derivatives, ((phenyl-amino)-(m)ethyl)-pyridine derivatives, tetrahydro-isoquinoline derivatives, 4-substituted piperidine analogues, 2-substituted piperidine derivatives, tri- or tetra-substituted guanidine derivatives, 3-hydroxy-4-imidazolidinone, 3-aminoquinoxalin-2-one derivatives, 1-amino-1-cyclobutanecarboxylic acid, thiamorphinan derivatives, pyrido[4,3-b]indole derivatives, 4-phenyl carbamoyl methylene tetrahydro quinoline-2-carboxylic acid or derivatives thereof, (3R,4S)-3-(4-(4-fluorophenyl)-4-hydroxy-piperidin-1-yl)-chroman-4,7-diol, indeno-pyrazin-4-one, 2,3-dioxo-1,2,4,5-tetrahydro-quinoxalinyl derivatives, 4,5-bridged quinoxalinedione or quinolone, (1S,2S)-1-(4-hydroxyphenyl)2-(4-hydroxy 4-phenyl piperidin-1-yl) 1-propanol methane sulphonate trihydrate, 4-sulphanimide-quinoline derivatives, methanobenzocyclodecen-13-amine, quinoxalinyl-(alkane, alkene, or alkyne)-phosphonic acid derivatives and esters, diarylalkylamine related to spider and wasp venom toxins, piperazine R-alpha-carboxylic acid derivatives, imidazo-indeno-pyrazin-4-one derivatives, pyridazino-quinoline derivatives, 1-substituted or 1,3-di-substituted 1,3-diaryl-guanidine, aza-cycloalkyl-fused quinoxaline-dione, 3-substituted 2-carboxy-indole derivatives or intermediates, (2R)-N-trityl-4-oxo-5-(dimethyl phosphono)-nor-valinate ester, kynurenic acid derivatives, indole carboxylic acid derivatives, 6-(tetrazolyl or isoxazolyl)-decahydroisoquinoline-3-carboxylic acid derivatives, phenyl- or pyridinyl-thieno-pyridinone derivatives, fused cycloalkyl-quinoxaline-dione derivatives, pyridazino-quinoline derivatives, 1-alpha-amino-3-biphenyl-propanoic acid derivatives, 3-(Indol-3-yl)propenoic acid derivatives, spiro-heterocycle-imidazo-indeno-pyrazine-4-one derivatives, 2-heterocyclyl-3-indolylpropenoic acid derivatives, piperidinoalkyl heterocyclic ketone, pyrrolyl-tetrahydro-benzoquinoxaline-dione derivatives, 7-imidazolyl or dialkylamino, tetrahydroquinoxaline dione, dibenzocycloheptene, quinoxaline derivatives, aryl-thio-quinoxaline derivatives, heterocyclic substituted imidazolo-quinoxaline derivatives, 1,4-dihydro-quinoxaline-2,3-dione derivatives, oxa- or thia-aliphatically bridged quinoxaline derivatives, aza-aliphatically bridged quinoxaline-2,3-dione, 3-amido- or 3-sulphamido-indole, 3,5-disubstituted phenyl-naphthalene derivatives, imidazo (1,2-a)indeno (1,2-e) pyrazine-2-carboxylic acid derivatives, 3-phenyl-fused ring pyridine-dione derivatives, 2-phenyl-pyridazino-indole-dione derivatives, 4,6-disubstituted kynurenine, phosphono derivatives of imidazo(1,2-a)pyrimidine-2-carboxamide, tetrahydro-quinoxaline-dione derivatives with N-(alkyl)carbonyl-amino- or ureido group, tryptophan derivatives, hetero-aliphatic or hetero-araliphatic substituted quinolone derivatives, imidazo-pyridine dicarboxylic acid derivatives, compositions containing pyrazolo-quinoline derivatives, ethanodihydrobenzoquinolizinium salt, oxopyridinylquinoxaline derivatives, indeno-triazolo-pyrazin-4-one derivatives, imidazo-indeno-pyrazinone derivatives, imidazo-indeno-pyrazin-4-one derivatives, imidazo(1,2-a)pyrazine-4-one derivatives, 5H-indeno-pyrazine-2,3-dione derivatives, phenyl-aminoalkyl-cyclopropane N,N-diethyl carboxamide, dexanabinol derivatives, substituted chroman derivatives, sulphonamide quinazoline-2-4-dione, 6- and 8-aza-, and 6,8-diaza-1,4-dihydro-quinoxaline-2,3-dione derivatives, substituted quinoline derivatives, tetrazolylalkyl cyclohexyl aminoalkanoic acid, tricyclic indole 2-carboxylic acid derivatives, 6-substituted-7H-imidazo-8-pyrazinone derivatives, tricyclic pyridazinopyridine derivatives, N-substituted heterocyclylidenemethyl-indole carboxylic acid derivatives, 3-aza-8-substituted-bicyclo(3.3.0)octane-2-carboxylic acid derivatives, ethano-heterocyclo-isoquinolinium, phenyl alkanolamine derivatives, dihydrobenzothiadiazinedioxide carboxylic acid derivatives, methyl-butenylmethyl(hydroxy-propyl)carbazoledione, imidazo pyrazinone derivatives, imidazo-(1,2-a)pyrazine-4-one, benzazepine-dione derivatives, disulfiram, 3-(indol-3-yl)-propenoic acid derivatives, 1,2,3,4-tetrahydro-quinoline-2,3,4-trione-3 or 4-oxime, 2-amino-2-phenyl(alkyl)-acetic acid derivatives, 6-halo-tryptophan or a 4-halo-kynurenine, 6-tetrazolyl or isoxazolyl-decahydro-isoquinoline-3-carboxylic acid derivatives, or imidazolylbenzene or salts thereof.
F. NMDA Receptor Channel Blockers
NMDA receptor channel blockers refer to compounds that reduce the permeability of channels associated with the NMDA receptor to cations (preferably to Na+, K+ and Ca2+ ions). NMDA receptor channel blockers can therefore be used to prevent a signal being transmitted due to ionic flux that would otherwise occur when glutamate binds to the NMDA receptor.
NMDA receptor channel blockers include i.e. magnesium, dizocilpine, phencyclidine, ketamine, memantine, tiletamine, budipine, flupirtine, 1-[1-(2-thienyl)cyclohexyl]piperidine (TCP), (+)-(3S,4S)-7-hydroxy-delta6-tetrahydrocannabinol-1,1-dimethylheptyl (HU211).
G. Glutamate Release Inhibitors
Such agents decrease the release of glutamate from nerve endings and prevent glutamate from binding to either AMPA, kainate, or NMDA binding sites and from triggering the signal that would occur as a result of binding of glutamate to these binding sites.
Glutamate release inhibitors include e.g. riluzole, lamotrigine, diphenylhydantoin, tetrodotoxin, agatoxin-glutamate-release-inhibitor (AG-GI), [5-(2,3,5-trichlorophenyl)]-2,4-diamino-pyrimidine (BW1003C87), (R)-(−)-5-methyl-1-nicotinoyl-2-pyrazoline (MS-153) and 4-amino-2-(4-methyl-1-piperazinyl)-5-(2,3,5-trichlorophenyl)pyrimidine (BW619C89).
H. Glycine Release Inhibitors
Such agents decrease the release of glycine from nerve endings and prevent glycine from binding to glycine B binding sites and from triggering the signal that would occur as a result of binding of glutamate to NMDA binding site.
I. Glutamate Synthesis Inhibitors and Drugs Interfering With Glutamate Metabolism
Such compounds block synthesis of glutamate or increase metabolism of glutamate preventing activation of either AMPA, kainate or NMDA binding sites.
Compounds interacting with glutamate synthesis or metabolism and preventing activation of either AMPA, kainate or NMDA receptors include e.g. gabapentin, L-canaline, phenylsuccinate, spermidine, putrescine, gentamicin, orthovanadate, vanadyl sulphate, vanadyl acetylacetonate, methionine sulphoximine, chloroquine, amodiaquine, quinacrine, chinidine, chinine, α-monofluoromethylputrescine and (R,R)-delta-methyl-α-acetylenic-putrescine.
J. Compounds Accelerating Glutamate Uptake
Such agents decrease synaptic concentration of glutamate by activating uptake mechanisms for glutamate preventing activation of either AMPA, kainate or NMDA receptors.
Compounds accelerating glutamate uptake mechanisms include e.g. γ-glutamyl-transpeptidase.
K. Agents That Interact With Glutamate and Prevent its Binding to its Receptors
Such agents include i.e. glutamate partial agonists which activate glutamate receptors by themselves but are less active than glutamate at these receptors and therefore decrease activation of these receptors by glutamate at physiological and excessively high concentrations or molecules binding to glutamate which change conformational state of glutamate and therefore decrease its binding capability to its receptors.
Glutamate partial agonists are e.g. D-serine, D-cycloserine, γ-L-glutamylglutamate, N-phthalamoyl-L-glutaminic acid, (R,S)-2-amino-3-[5-tert-butyl-3-(phosphonomethoxy)-4-isoxazolyl]propionic acid, α-N-acetylaspartylglutamate, 1-aminocyclopropanecarboxylic acid, aminocyclobutane cyrboxylic acid, (+,R)-3-amino-1-hydroxy-2-pyrrolidine (HA966) and D,L-threo-3-hydroxyasparate.
Furthermore such agents include soluble forms of NMDA, kainate or AMPA receptors or parts thereof. These soluble forms can be used to circulate and to bind to glutamate and therefore decrease its binding capability to the receptors. Membrane bound forms of the glutamate receptors may also be incorporated into liposomes, circulate and bind to glutamate so as to prevent it binding to its receptors.
L. Agents That Interact With Glutamate Transporter Systems
Such agents accelerate glutamate transporter function and decrease glutamate concentration at its receptors preventing activation of either AMPA, kainate or NMDA receptors.
Such agents include e.g. 12-O-tetradecanoylphorbol-13-acetate, phorbol-12-myristate 13-acetate.
M. Antibodies Interacting With AMPA Receptors or With Glutamate
The AMPA, kainate or NMDA receptors or a part or parts of them, or glutamate can be used for raising antibodies that bind thereto. Preferred antibodies bind specifically to either AMPA, kainate or NMDA receptor or a part thereof, or to glutamate. The antibodies may be monoclonal or polyclonal. Polyclonal antibodies can be raised by stimulating their production in a suitable animal host (e.g. a mouse, rat, guinea pig, rabbit, sheep, goat or monkey) when either AMPA, kainate or NMDA receptor, or a part thereof, or glutamate is injected into the animal. If necessary an adjuvant may be administered together with the AMPA, kainate or NMDA receptor, or a part thereof, or with glutamate. In addition to whole antibodies, antagonists of the present invention include derivatives thereof.